Artificial lift system and an associated method thereof

ABSTRACT

An artificial lift system and a method of operating and installing such an artificial lift system are disclosed. The artificial lift system includes a reciprocating driver and a reciprocating pump. Further, the reciprocating driver includes a driver-shaft and the reciprocating pump includes a pump-shaft detachably engaged to the driver-shaft. In one embodiment, the artificial lift system further includes a coupling member, where the pump-shaft is detachably engaged to the driver-shaft through the coupling member.

BACKGROUND

Embodiments of the present invention relate to an artificial lift system, and more particularly, to a coupling member used to detachably engage a reciprocating pump to a reciprocating driver of the artificial lift system.

Artificial lift systems are generally used in a production well, where there is insufficient pressure in a reservoir for lifting production fluids from the reservoir to the Earth's surface. The artificial lift system typically includes one or more pumping systems disposed in the production well and configured to pump the production fluids from the reservoir to the Earth's surface.

Typically, the pumping system may include an electrical submersible pump (ESP) system which is configured to pump the production fluids from the reservoir having a wide range of flow rates and lift requirements. However, the ESP system may not be suitable for a low volume production well having high dog leg severity. In such conditions, a linear pumping system may be used as an alternative pumping system. Such a pumping system includes a pump and a motor which are generally coupled to each other and disposed coaxially on a production tubing in the production well or in a production casing of the production well attached to the production tubing. The pump used in such a pumping system has a statistically high rate of failure and may need to be frequently repaired or replaced independent of the motor and the production tubing. However, the conventional pumping system requires a whole unit (i.e. pump, motor, and the production tubing) to be removed from the production well to the Earth's surface for replacement and/or repair of the pump. As a result, service costs, time required for replacement, and the amount of production downtime is increased.

Accordingly, there is a need for a coupling member for an artificial lift system and an associated method for operating and installing such an artificial lift system.

BRIEF DESCRIPTION

In accordance with one exemplary embodiment of the present invention, an artificial lift system is disclosed. The artificial lift system includes a reciprocating driver and a reciprocating pump. In one exemplary embodiment, the reciprocating driver includes a driver-shaft and the reciprocating pump includes a pump-shaft detachably engaged to the driver-shaft.

In accordance with another exemplary embodiment of the present invention, a method for installing an artificial lift system including a reciprocating driver and a reciprocating pump is disclosed. The method involves installing the reciprocating driver including a driver-shaft and the reciprocating pump including a pump-shaft in the well bore. The method further involves applying a force to the reciprocating pump, to detachably engage the pump-shaft to the driver-shaft.

In accordance with another exemplary embodiment of the present invention, a method of operating an artificial lift system including a reciprocating driver and a reciprocating pump is disclosed. The method involves powering the reciprocating driver disposed in a well bore and driving the reciprocating pump disposed in the well bore via the reciprocating driver. The reciprocating driver includes a driver-shaft and reciprocating pump includes a pump-shaft detachably engaged to the driver-shaft. The method further involves pumping a production fluid from the well bore to a surface unit via tubing by driving the reciprocating pump.

DRAWINGS

These and other features and aspects of embodiments of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:

FIG. 1 is a schematic view of an artificial lift system disposed in a production well in accordance with one exemplary embodiment;

FIG. 2 is a schematic disassembled view of a driver-shaft, a pump-shaft, and a coupling member of the artificial lift system in accordance with the embodiment of FIG. 1;

FIG. 3 is a schematic assembled view of the driver-shaft, the pump-shaft, and the coupling member in accordance with the embodiment of FIGS. 1 and 2;

FIG. 4 is a schematic disassembled view of a driver-shaft, a pump-shaft, and a coupling member of an artificial lift system in accordance with another exemplary embodiment;

FIG. 5 is a schematic assembled view of the driver-shaft, the pump-shaft, and the coupling member in accordance with the embodiment of FIG. 4;

FIG. 6 is a schematic disassembled view of a driver-shaft, a pump-shaft, and a coupling member of an artificial lift system in accordance with yet another exemplary embodiment;

FIG. 7 is a schematic assembled view of the driver-shaft, the pump-shaft, and the coupling member in accordance with the embodiment of FIG. 6;

FIG. 8 is a schematic disassembled view of a driver-shaft, a pump-shaft, and a coupling member of an artificial lift system in accordance with yet another exemplary embodiment;

FIG. 9 is a schematic assembled view of the driver-shaft, the pump-shaft, and the coupling member in accordance with the embodiment of FIG. 8;

FIG. 10 is a schematic disassembled view of a driver-shaft, a pump-shaft, and a coupling member of an artificial lift system in accordance with yet another exemplary embodiment;

FIG. 11 is a schematic assembled view of the driver-shaft, the pump-shaft, and the coupling member in accordance with the embodiment of FIG. 10;

FIG. 12 is a schematic disassembled view of a driver-shaft, a pump-shaft, and a coupling member of an artificial lift system in accordance with yet another exemplary embodiment;

FIG. 13 is a schematic assembled view of the driver-shaft, the pump-shaft, and the coupling member in accordance with the embodiment of FIG. 12; and

FIG. 14 is a schematic assembled view of a driver-shaft coupled directly to a pump-shaft of an artificial lift system in accordance with one exemplary embodiment.

DETAILED DESCRIPTION

Embodiments discussed herein disclose an artificial lift system configured for extracting production fluids from one or more reservoirs. In certain embodiments, the artificial lift system is disposed in a production well and is configured to pump the production fluids from the reservoirs to a surface unit through a production tubing disposed in a well bore. In one embodiment, the artificial lift system includes a reciprocating driver and a reciprocating pump. In such embodiments, the reciprocating driver includes a driver-shaft and the reciprocating pump includes a pump-shaft detachably engaged to the driver-shaft. In some embodiments, the artificial lift system further includes a coupling member. In such embodiments, the coupling member may be coupled to the pump-shaft, wherein the pump-shaft is detachably engaged to the driver-shaft via the coupling member. In some other embodiments, the coupling member may be coupled to the driver-shaft, wherein the pump-shaft is detachably engaged to the driver-shaft via the coupling member. In one or more embodiments, the reciprocating pump may be detachably coupled to the reciprocating driver within the production tubing of the well bore, thereby allowing the reciprocating pump to be easily and efficiently replaced independently of the reciprocating driver and the production tubing. As a result, service costs, time required for replacement/repair of the reciprocating pump, and deferred production are reduced.

FIG. 1 illustrates a schematic view of an artificial lift system 100 disposed in a production well 104 in accordance with one exemplary embodiment. The artificial lift system 100 may be located at depths reaching several thousands of meters in a production tubing 102 disposed in the production well 104 and proximate to a hydrocarbon reservoir 106.

In one embodiment, the artificial lift system 100 includes a reciprocating pump 108 and a reciprocating driver 110. The production tubing 102 is disposed within a well bore 112 of the production well 104. The well bore 112 includes a plurality of perforations 114 which is configured to allow production fluids 116 from the hydrocarbon reservoir 106 to enter the well bore 112. The production tubing 102 includes a plurality of holes 118 which is configured to allow the production fluids 116 from the well bore 112 to enter the production tubing 102. In one embodiment, the production fluids 116 include a mixture of oil, water, and gas.

In one embodiment, the reciprocating driver 110 is a reciprocating motor. In certain embodiments, the reciprocating motor is an induction motor. In certain other embodiments, the reciprocating motor includes a permanent magnet configured to produce a substantially straight-line motion using a linear stator and a rotor placed in parallel to the linear stator. It should be noted herein that the terms, “reciprocating driver” and “reciprocating motor” are used interchangeably. The reciprocating driver 110 includes a casing 120 coupled to an end portion 122 of the production tubing 102. The reciprocating driver 110 includes a driver-shaft 126 coupled to the rotor and configured to reciprocate along the casing 120. In some embodiments, the rotor itself acts as the driver-shaft 126. The reciprocating driver 110 is powered via an electric cable 124 coupled to a power supply unit (not shown in FIG. 1). In one embodiment, the power supply unit may be disposed within the well bore 112 or on a surface 128 of Earth. In the illustrated embodiment, the casing 120 of the reciprocating driver 110 is surrounded by the production fluids 116. In such embodiments, the casing 120 may include one or more seals to prevent the entry of production fluids 116 and damaging the reciprocating driver 110. In one or more embodiments, the production fluids 116 may be used to cool the reciprocating driver 110. Although the reciprocating driver 110 is described herein, in other embodiments, the reciprocating driver 110 may include, but not limited to, a rotary to linear conversion device and hydraulic pressure device delivering hydraulic pressure from the Earth's surface.

The reciprocating pump 108 is disposed within the production tubing 102. In one embodiment, the reciprocating pump 108 is a reciprocating pump having a piston and a pump-shaft 132 coupled to the piston. The reciprocating pump 108 is configured to pump the production fluids 116 from the well bore 112. In the illustrated embodiment, the reciprocating pump 108 includes a casing 130 and the pump-shaft 132 coupled to the driver-shaft 126 and configured to reciprocate along the casing 130. It should be noted herein that the term “coupled” is referred to as detachably engaged. The reciprocating pump 108 may be supported by packer members (not shown in FIG. 1) disposed between the production tubing 102 and the casing 130. The packer members are configured to additionally prevent a flow of the production fluids 116 back into the well bore 112 along a gap (not labeled) between the casing 130 and the production tubing 102.

In the illustrated embodiment, the artificial lift system 100 further includes a coupling member 136. Specifically, the pump-shaft 132 is detachably engaged to the driver-shaft 126 via the coupling member 136.

During operation, the reciprocating driver 110 is powered via the electric cable 124, which causes the driver-shaft 126 to reciprocate along the casing 120 and drive the reciprocating pump 108. Specifically, the reciprocating motion of the driver-shaft 126 drives the pump-shaft 132, so as to pump the production fluids 116 from the well bore 112 to a surface unit 134 via the production tubing 102. In some embodiments, the surface unit 134 may be a storage facility, a fluid processing unit, and the like. In one embodiment, the reciprocating motion produced by the reciprocating driver 110 to drive the reciprocating pump 108 includes an upward stroke and downward stroke. During upward stroke, a compressive force is exerted by the reciprocating driver 110 to the reciprocating pump 108, which is transmitted directly from the driver-shaft 126 to the pump-shaft 132 bypassing the coupling member 136. In other words, driving the reciprocating pump 108 includes transmitting a compressive force directly from the driver-shaft 126 to the pump-shaft 132. During downward stroke, a tensile force is exerted by the reciprocating pump 108 to the reciprocating driver 110, which is transmitted from the pump-shaft 132 to the driver-shaft 126 via the coupling member 136. In other words, driving the reciprocating pump 108 includes transmitting a tensile force from the pump-shaft 132 to the driver-shaft 126 via the coupling member 136.

In one embodiment, during installation, the reciprocating driver 110 along with the production tubing 102 is installed in the well bore 112, via a wireline unit, a slickline, a rig, or the like (not shown in FIG. 1). The installation of the reciprocating driver 110 involves disposing the reciprocating driver 110 proximate to the plurality of perforations 114 formed in the well bore 112. Further, the reciprocating pump 108 is installed within the production tubing 102 via the wireline, the slickline, the rig, and the like. The installation of the reciprocating pump 108 involves disposing the pump-shaft 132 substantially proximate to the driver-shaft 126. The pump-shaft 132 is then detachably engaged to the driver-shaft 126 by applying a first force 137 to the reciprocating pump 108. Specifically, the first force 137 is applied on the reciprocating pump 108 to engage the pump-shaft 132 to the driver-shaft 126. The first force 137 is applied along a first direction 138 which is oriented into the well bore 112. In some embodiments, the first force 137 is at least one of a linear force and a rotational force, applied using a drive unit 140. The drive unit 140 includes at least one of a hydraulic pressure device 140 a, a pneumatic pressure device 140 b, a wire line device 140 c, a coiled tubing 140 d, and a plurality of sucker rods 140 e. The drive unit 140 is configured to apply the first force 137, for example, the linear force on the reciprocating pump 108 to engage the pump-shaft 132 to the driver-shaft 126. In the illustrated embodiment, the drive unit 140 is coupled to a tubing string 144 of the reciprocating pump 108 via the coupling member 136. In some embodiments, the drive unit 140 may be directly coupled to the tubing strings 144 via screw elements (threaded elements).

In some embodiments, during maintenance of the artificial lift system 100, the reciprocating pump 108 is disengaged from the reciprocating driver 110 by applying a second force 145. Specifically, the second force 145 is applied on the reciprocating pump 108 to disengage the pump-shaft 132 from the driver-shaft 126. In some embodiments, the maintenance of the artificial lift system 100 may include repair or replacement of the reciprocating pump 108. Specifically, the second force 145 is applied along a second direction 146 which is oriented away from the well bore 112. In some embodiments, the second force 145 is at least one of a linear force and a rotation force, applied using the drive unit 140.

In one or more embodiments, the reciprocating pump 108 is detachably engaged to the reciprocating driver 110 within the well bore 112. As a result, there is no need to remove the whole unit (i.e. reciprocating driver 110, the production tubing 102, and the reciprocating pump 108) from the well bore 112 during maintenance, thereby, reducing service costs, time required for replacement/repair of the reciprocating pump 108 and the reciprocating driver 110, and the amount of production downtime.

FIG. 2 shows a schematic disassembled view of the driver-shaft 126, the pump-shaft 132, and the coupling member 136 of the artificial lift system 100 in accordance with one exemplary embodiment.

The driver-shaft 126 includes a first peripheral end portion 148 and a second peripheral end portion 150. The driver-shaft 126 further includes a notch 152 disposed substantially proximate to the first peripheral end portion 148. Further, the notch 152 extends along a circumferential direction of the driver-shaft 126 and has a depth “D₁”. The notch 152 includes a first inclined portion 154 and a second inclined portion 156 connected to the first inclined portion 154 through a flat portion 158. The first inclined portion 154 is tilted at a first predetermined angle “A₁” and the second inclined portion 156 is tilted at a second predetermined angle “A₂” relative to a central axis 149. The first peripheral end portion 148 includes a tapered portion 160 extending along a circumferential direction of the driver-shaft 126. The tapered portion 160 is tilted at a third predetermined angle “A₃” relative to the central axis 149. In one embodiment, the second peripheral end portion 150 is coupled to the rotor of the reciprocating driver and configured to reciprocate along the casing of the reciprocating driver. In some other embodiments, the driver-shaft 126 may be the rotor of the reciprocating driver.

The coupling member 136 is a hollow component. In the illustrated embodiment, the coupling member 136 has a cylindrical shape. The coupling member 136 includes a first end 162 and a second end 164. In one embodiment, the first end 162 includes a plurality of screw elements 166 disposed circumferentially along an inner surface 168 of the coupling member 136. The coupling member 136 includes a plurality of tines 170 extending from the second end up to a predefined distance towards the first end 162. The plurality of tines 170 is spaced apart from each other and disposed along the circumferential direction of the coupling member 136. Each tine 170 includes a projection 172 disposed at the second end 164 of the coupling member 136. In the illustrated embodiment, the projection 172 protrudes radially inward towards a central axis 163. In one embodiment, the projection 172 includes a first inclined portion 174 and a second inclined portion 176 connected to the first inclined portion 174 through a flat portion 178. The first inclined portion 174 is tilted at a first predetermined angle “A₄” and the second inclined portion 176 is tilted at a second predetermined angle “A₅” relative to the central axis 163. The coupling member 136 is made of relatively flexible material. In one embodiment, the flexible material includes at least one of a stainless steel material, carbon steel, nickel alloy, and nickel-chromium super alloy.

The pump-shaft 132 includes a first peripheral end portion 180 and a second peripheral end portion 182. The first peripheral end portion 180 has a diameter “D₂” and the second peripheral end portion 182 has a diameter “D₃”. In the illustrated embodiment, the diameter “D₂” is smaller than diameter “D₃”. Further, the first peripheral end portion 180 includes a plurality of screw elements 184 disposed circumferentially along an outer surface 186 of the pump-shaft 132. In one embodiment, the second peripheral end portion 182 is coupled to the connecting rod of the reciprocating pump and configured to reciprocate along the casing of the reciprocating pump for pumping the production fluids. In some other embodiments, the pump-shaft 132 itself may be the connecting rod of the reciprocating driver.

In one embodiment, the first predetermined angle “A₁” of the driver-shaft 126 is substantially equal to the first predetermined angle “A₄” of the coupling member 136. The second predetermined angle “A₂” and the third predetermined angle “A₃” of the driver-shaft 126 are substantially equal to the second predetermined angle “A₅” of the coupling member 136. During design stage, the first predetermined angles “A₁” and “A₄” may be determined based on a force required by the reciprocating pump to be pulled into wellbore by the reciprocating driver without getting disengaged from the coupling member 136. Further, the second predetermined angles “A₂”, “A₄”, and the third predetermined angle “A₄” may be determined based on a compressive force required to engage the coupling member 136. During the power stroke, the reciprocating driver is configured to push the reciprocating pump to lift the production fluids. During such an event, compressive force applied by the reciprocating driver gets transmitted directly from the driver-shaft 126 to the pump-shaft 132 bypassing the coupling member 136. In other words, the compressive force is transmitted by contacting the first peripheral end portion 148 of the driver-shaft 126 with the first peripheral end portion 180 of the pump-shaft 132. During the return stroke, the reciprocating driver is configured to pull (apply tensile force) the reciprocating pump into down position i.e. into the wellbore. During such an event, the tensile force is transmitted by contacting the first inclined portion 174 of the coupling member 136 with the first inclined portion 154 of the notch 152.

FIG. 3 shows a schematic assembled view of the driver-shaft 126, the pump-shaft 132, and the coupling member 136 in accordance with the embodiments of FIGS. 1 and 2.

In one embodiment, the pump-shaft 132 is coupled to the coupling member 136 via the screw elements 166, 184. Further, the pump-shaft 132 is detachably engaged to the driver-shaft 126 via the coupling member 136. Specifically, the projection 172 of the coupling member 136 is detachably engaged to the notch 152 of the driver-shaft 126 such that the first peripheral end portion 180 of the pump-shaft 132 is contacted to the first peripheral end portion 148 of the driver-shaft 126.

During assembly and prior to installation in the well bore, the screw elements 166 are rotated over the screw elements 184 for coupling the coupling member 136 to the pump-shaft 132. Further, during installation in the well bore, a first force 137 is applied on the reciprocating pump 108 such that the plurality of tines 170 is expanded outwardly, thereby allowing the projection 172 to pass along the first peripheral end portion 148 of the driver-shaft 126. The plurality of tines 170 is further contracted when the projection 172 engages the notch 152, thereby allowing the pump-shaft 132 to detachably engage to the driver-shaft 126. In one embodiment, the first force 137 is a linear force applied along the first direction 138 (as shown in FIG. 1) into the well bore 112. During maintenance, the second force 145 is applied on the reciprocating pump 108 such that the plurality of tines 170 is expanded permitting the projection 172 to detach from the notch 152, thereby allowing the pump-shaft 132 to disengage from the driver-shaft 126. In one embodiment, the second force 145 is the linear force applied along the second direction 146 (as shown in FIG. 1) away from the well bore 112.

In certain other embodiments, the pump-shaft 132 may include the notch 152 and the tapered portion 160. The driver-shaft 126 may include the plurality of screw elements 184. In such embodiments, the driver-shaft 126 may be coupled to the coupling member 136 via the screw elements 166, 184. Further, the driver-shaft 126 may be detachably engaged to the pump-shaft 132 via the coupling member 136. Specifically, the projection 172 of the coupling member 136 may be detachably engaged to the notch 152 of the pump-shaft 132.

FIG. 4 shows a schematic disassembled view of a driver-shaft 226, a pump-shaft 232, and a coupling member 236 of an artificial lift system in accordance with another exemplary embodiment.

In the illustrated embodiment, the driver-shaft 226 includes a first peripheral end portion 248 and a second peripheral end portion 250. The pump-shaft 232 includes a first peripheral end portion 280 and a second peripheral end portion 282. The coupling member 236 includes a harpoon anchor 286 and a connecting member 288 configured to detachably engage to the harpoon anchor 286. In the illustrated embodiment, the harpoon anchor 286 is coupled to the pump-shaft 232. Specifically, the harpoon anchor 286 is coupled to an outer surface 294 of the pump-shaft 232 and is disposed at the first peripheral end portion 280. The connecting member 288 is coupled to the driver-shaft 226. Specifically, the connecting member 288 includes a first end 228 and a second end 230. The second end 230 is coupled to the first peripheral end portion 248 of the driver-shaft 226. In other words, the harpoon anchor 286 is coupled to one among the driver-shaft 226 and the pump-shaft 232 and the connecting member 288 is coupled to other among the pump-shaft 232 and the driver-shaft 226.

In certain other embodiments, the connecting member 288 may be coupled to the pump-shaft 232 and the harpoon anchor 286 may be coupled to the driver-shaft 226 depending on the application and design criteria.

The connecting member 288 includes a slot 284 disposed substantially along a longitudinal direction from the first end 228 towards the second end 230. The slot 284 includes a first slot portion 290 and a second slot portion 292. The first slot portion 290 has a diameter “D₁” and the second slot portion 292 has a diameter “D₂” different from the diameter “D₁”. In one embodiment, the diameter “D₂” is larger than the diameter “D₁”. In the illustrated embodiment, the harpoon anchor 286 has a triangular shape. The harpoon anchor 286 is configured to move inwardly and outwardly relative to a central axis 296 of the pump-shaft 232. The inward and outward movement of the harpoon anchor 286 may be generated by a biasing member, such as a spring and the like. The second slot portion 292 is configured to receive the harpoon anchor 286 and thereby detachably engage the pump-shaft 232 to the driver-shaft 226.

FIG. 5 shows a schematic assembled view of the driver-shaft 226, the pump-shaft 232, and the coupling member 236 in accordance with the embodiment of FIG. 4. In one embodiment, the pump-shaft 232 is detachably engaged to the driver- shaft 226 via the coupling member 236. In the illustrated embodiment, a portion of the pump-shaft 232 is disposed within the first slot portion 290 and the harpoon anchor 286 is detachably engaged to the second slot portion 292.

During installation a first force 237 is applied on a reciprocating pump such that the harpoon anchor 286 moves inwardly towards the central axis 296, thereby allowing the portion of the pump-shaft 232 to pass through the first slot portion 290. The harpoon anchor 286 moves outwardly away from the central axis 296 when the harpoon anchor 286 reaches the second slot portion 292, thereby allowing the pump-shaft 232 to detachably engage to the driver-shaft 226. In one embodiment, the first force 237 is a linear force applied along a first direction into a well bore. During maintenance, the second force 245 is applied on the reciprocating pump such that harpoon anchor 286 is sheared off, thereby allowing the pump-shaft 232 to disengage from the driver-shaft 226. In one embodiment, the second force 245 is the linear force applied along a second direction away from the well bore.

FIG. 6 shows a schematic disassembled view of a driver-shaft 326, a pump-shaft 332, and a coupling member 336 of an artificial lift system in accordance with yet another exemplary embodiment.

In the illustrated embodiment, the driver-shaft 326 includes a first peripheral end portion 348 and a second peripheral end portion 350. The pump-shaft 332 includes a first peripheral end portion 380 and a second peripheral end portion 382. The coupling member 336 includes a plurality of shear pins 386 and a connecting member 388 configured to detachably engage to the plurality of shear pins 386. In the illustrated embodiment, each shear pin 386 is coupled to the pump-shaft 332. Specifically, each shear pin 386 is coupled to a peripheral surface 398 of the pump-shaft 332 and disposed proximate to the first peripheral end portion 380. The connecting member 388 is coupled to the driver-shaft 326. Specifically, the connecting member 388 includes a first end 328 and a second end 330. The second end 330 is coupled to the first peripheral end portion 348 of the driver-shaft 326. In other words, each shear pin 386 is coupled to one among the driver-shaft 326 and the pump-shaft 332 and the connecting member 388 is coupled to other among the pump-shaft 332 and the driver-shaft 326.

In certain other embodiments, the connecting member 388 may be coupled to the pump-shaft 332 and each shear pin 386 may be coupled to the driver-shaft 326 depending on the application and design criteria.

The connecting member 388 includes a plurality of slots 384. It should be noted herein that only one slot of the plurality of slots 384 is shown in the illustrated embodiment and such illustration should not be construed as a limitation of the present invention. In one embodiment, each slot of the plurality of slots 384 is disposed on a peripheral surface 397 of the connecting member 388 and disposed along a longitudinal direction from the first end 328 towards the second end 330. Each slot of the plurality of slots 384 includes a first slot portion 378, a second slot portion 390, and a third slot portion 392 having a detent portion 393 disposed at a downstream end. In the illustrated embodiment, each slot of the plurality of slots 384 has a “J” shape. Each shear pin 386 is configured to rotate inside a first slot portion 378, slide along the second slot portion 390, and rotatably engage to the third slot portion 392. In one embodiment, the third slot portion 392 is configured to receive each shear pin 386 and thereby detachably engage the pump-shaft 332 to the driver-shaft 326.

FIG. 7 shows a schematic assembled view of the driver-shaft 326, the pump-shaft 332, and the coupling member 336 in accordance with the embodiment of FIG. 6. In one embodiment, the pump-shaft 332 is detachably engaged to the driver-shaft 326 via the coupling member 336. In the illustrated embodiment, a portion of the pump-shaft 332 is disposed within the slot 384 and each shear pin of the plurality of shear pins 386 is detachably engaged to the detent portion 393 of the slot 384.

During installation, a first force 337 is applied on a reciprocating pump such that each shear pin 386 rotates inside the first slot portion 378. Further, each shear pin 386 slides along the second slot portion 390, thereby allowing the portion of the pump-shaft 332 to engage with the slot 384. Each shear pin 386 is further passed through the third slot portion 392 and rotatably engaged to the detent portion 393 portion, thereby allowing the pump-shaft 332 to detachably engage with the driver-shaft 326. In one embodiment, the first force 337 is a combination of a linear force and a rotational force applied along a first direction into a well bore. During maintenance, a second force 345 is applied on the reciprocating pump such that each shear pin 386 is sheared off, thereby allowing the pump-shaft 332 to disengage from the driver-shaft 326. In one embodiment, the second force 345 is the linear force applied along a second direction away from the well bore. In some other embodiments, during maintenance, the second force 345 is applied on the reciprocating pump such that each shear pin 386 is rotatably disengaged from the third slot portion 392, linearly slide back from the second slot portion 390, and rotatably disengaged from the first slot portion 378. In such embodiments, the second force 345 is a combination of the linear force and the rotational force applied along the second direction into a well bore.

FIG. 8 shows a schematic disassembled view of a driver-shaft 426, a pump-shaft 432, and a coupling member 436 of an artificial lift system in accordance with yet another exemplary embodiment.

In the illustrated embodiment, the driver-shaft 426 includes a first peripheral end portion 448 and a second peripheral end portion 450. The pump-shaft 432 includes a first peripheral end portion 480 and a second peripheral end portion 482. The coupling member 436 includes an overshot member 486 and a fishing-neck-like member 488 configured to detachably engage the overshot member 486. In the illustrated embodiment, the fishing-neck-like member 488 is coupled to the driver-shaft 426. Specifically, the fishing-neck-like member 488 includes a first end 428 and a second end 430. The second end 430 is coupled to the first peripheral end portion 448 of the driver-shaft 426. The overshot member 486 is coupled to the pump-shaft 432. Specifically, the overshot member 486 includes a first end 468 and a second end 470. The second end 470 is coupled to the first peripheral end portion 480 of the pump-shaft 432. In other words, the fishing-neck-like member 488 is coupled to one among the driver-shaft 426 and the pump-shaft 432 and the overshot member 486 is coupled to other among the pump-shaft 432 and the driver-shaft 426.

In certain other embodiments, the overshot member 486 may be coupled to the driver-shaft 426 and the fishing-neck-like member 488 may be coupled to the pump-shaft 432 depending on the application and design criteria.

The fishing-neck-like member 488 includes a body portion 490 coupled to the first peripheral end portion 448 and a tapered portion 492 coupled to the body portion 490. The overshot member 486 has a body portion 440 and a plurality of tapered portions 442 stacked to one another. The plurality of tapered portions 442 of the overshot member 486 is configured to receive the tapered portion 492 of the fishing-neck-like member 488 and thereby detachably engage the pump-shaft 432 to the driver-shaft 426.

FIG. 9 shows a schematic assembled view of the driver-shaft 426, the pump-shaft 432, and the coupling member 436 in accordance with the embodiment of FIG. 8. In one embodiment, the pump-shaft 432 is detachably engaged to the driver-shaft 426 via the coupling member 436. In the illustrated embodiment, the fishing-neck-like member 488 is disposed within the overshot member 486 to detachably engage the tapered portion 492 (shown in FIG. 8) to at least one tapered portion of the plurality of tapered portions 442.

During installation a first force 437 is applied on a reciprocating pump such that the overshot member 486 slides over the fishing-neck-like member 488, thereby allowing the plurality of tapered portions 442 to pass along the tapered portion 492. At least one tapered portion of the plurality of tapered portions 442 locks the tapered portion 492, thereby allowing the pump-shaft 432 to detachably engage with the driver-shaft 426. In one embodiment, the first force 437 is a linear force applied along a first direction into a well bore. During maintenance, a second force 445 is applied on the reciprocating pump such that tapered portion 492 is detached from the at least one tapered portion of the plurality of tapered portions 442, thereby allowing the pump-shaft 432 to disengage from the driver-shaft 426. In one embodiment, the second force 445 is the linear force applied along a second direction away from the well bore. In one embodiment, the first force 437 and the second force 445 are applied using a plurality of springs, such as “C”-shaped springs or a hydraulic pressure device delivering hydraulic pressure from the Earth's surface.

FIG. 10 shows a schematic disassembled view of a driver-shaft 526, a pump-shaft 532, and a coupling member 536 of an artificial lift system in accordance with yet another exemplary embodiment.

In one embodiment, the driver-shaft 526 includes a first peripheral end portion 548 and a second peripheral end portion 550. The pump-shaft 532 includes a first peripheral end portion 580 and a second peripheral end portion 582. The coupling member 536 includes a spring collet 586, a first connecting member 588, and a second connecting member 594. The first connecting member 588 is configured to detachably engage the spring collet 586. In the illustrated embodiment, the first connecting member 588 is coupled to the driver-shaft 526. Specifically, the first connecting member 588 includes a first end 528 and a second end 530. The second end 530 is coupled to the first peripheral end portion 548 of the driver-shaft 526. The spring collet 586 is coupled to the pump-shaft 532 through the second connecting member 594. Specifically, the second connecting member 594 includes a first end 560 and a second end 562. The second end 562 is coupled to the pump-shaft 532 through a plurality of shear pins 578. Further, the spring collet 586 is coupled to the first end 560 of the second connecting member 594. In other words, the spring collet 586 is coupled to one among the driver-shaft 526 and the pump-shaft 532 and the first connecting member 588 is coupled to other among the pump-shaft 532 and the driver-shaft 526.

In certain other embodiments, the first connecting member 588 may be coupled to the pump-shaft 532 and the spring collet 586 may be coupled to the driver-shaft 526 through the second connecting member 594 depending on the application and design criteria.

The first connecting member 588 includes a slot 584 disposed along a longitudinal direction from the first end 528 towards the second end 530. The slot 584 includes a first slot portion 590 and a second slot portion 592. In the illustrated embodiment, the second slot portion 592 is disposed substantially perpendicular relative to a central axis 583 of the driver-shaft 526. The second connecting member 594 includes a slot 556 disposed at the second end 562 and substantially along the longitudinal direction from the second end 562 towards the first end 560. The slot 556 includes a first slot portion 544 and a second slot portion 546 (shoulder portion). In the illustrated embodiments, the first slot portion 544 and the second slot portion 546 of the slot 556 have a substantially similar dimension as that of the first slot portion 590 and the second slot portion 592 of the slot 584 of the first connecting member 588. The spring collet 586 includes a body portion 552 and a shoulder portion 554. The body portion 552 and the shoulder portion 554 of the spring collet 586 have a substantially similar dimension as that of the first slot portion 590 and the second slot portion 592 of the first connecting member 588. In the illustrated embodiment, the shoulder portion 554 is disposed substantially perpendicular relative to a central axis 581 of the pump-shaft 532. In one embodiment, the second slot portion 592 of the first connecting member 588 is configured to receive the shoulder portion 554 of the spring collet 586 and thereby detachably engage the pump-shaft 532 to the driver-shaft 526.

FIG. 11 shows a schematic assembled view of the driver-shaft 526, the pump-shaft 532, and the coupling member 536 in accordance with the embodiment of FIG. 10. In one embodiment, the pump-shaft 532 is detachably engaged to the driver-shaft 526 via the coupling member 536. In the illustrated embodiment, the spring collet 586 is disposed within the slot 584 to detachably engage the shoulder portion 554 of the spring collet 586 to the second slot portion 592 of the slot 584.

During installation, a first force 537 is applied on a reciprocating pump such that the shoulder portion 554 of the spring collet 586 passes through first slot portion 590 (shown in FIG. 10) of the slot 584 and detachably engage to the second slot portion 592 of the slot 584. In one embodiment, the first force 537 is a linear force applied along a first direction into a well bore. During maintenance, a second force 545 is applied on the reciprocating pump such that the plurality of shear pins 578 is sheared off from the second connecting member 594, thereby allowing the pump-shaft 532 to disengage from the driver-shaft 526. In such embodiments, the second connecting member 594 is retained with the driver-shaft 526. The slot 556 of the second connecting member 594 is configured to receive and hold a new spring collet. In one embodiment, the second force 545 is the linear force applied along a second direction away from the well bore.

FIG. 12 shows a schematic disassembled view of a driver-shaft 626, a pump-shaft 632, and a coupling member 636 of an artificial lift system in accordance with yet another exemplary embodiment.

The coupling member 636 includes a spring collet 686 and a connecting member 688 configured to detachably engage to the spring collet 686. In the illustrated embodiment, the connecting member 688 is coupled to the driver-shaft 626. Specifically, the driver-shaft 626 includes a peripheral end portion 648 coupled to a peripheral end portion 630 of the connecting member 688. The spring collet 686 is coupled to the pump-shaft 632. Specifically, the pump-shaft 632 includes a peripheral end portion 644 coupled to a peripheral end portion 662 of the spring collet 686. In certain other embodiments, the connecting member 688 may be coupled to the pump-shaft 632 and the spring collet 686 may be coupled to the driver-shaft 626 depending on the application and design criteria.

The connecting member 688 includes a slot 684 having a first slot portion 690 and a second slot portion 692. It should be noted herein that the side walls of the second slot portion 692 are tilted at a pre-determined tilt angle relative to a central axis 683 of the driver-shaft 626. In the illustrated embodiment, the pump-shaft 632 is a stepped shaft directly coupled to the spring collet 686. The spring collet 686 includes a shoulder portion 654 having side walls disposed at a pre-determined tilt angle relative to a central axis 681 of the pump-shaft 632. In one embodiment, the second slot portion 692 of the connecting member 688 is configured to receive the shoulder portion 654 of the spring collet 686 and thereby detachably engage the pump-shaft 632 to the driver-shaft 626.

FIG. 13 shows a schematic assembled view of the driver-shaft 626, the pump-shaft 632, and the coupling member 636 in accordance with the embodiment of FIG. 12. The pump-shaft 632 is detachably engaged to the driver-shaft 626 via the coupling member 636. In the illustrated embodiment, the spring collet 686 is disposed within the slot 684 (shown in FIG. 10) to detachably engage the shoulder portion 654 of the spring collet 686 to the second slot portion 692 of the slot 684.

During installation, a first force 637 is applied on a reciprocating pump such that the shoulder portion 654 of the spring collet 686 passes through the slot 684 to detachably engage to the second slot portion 692 of the slot 684. In one embodiment, the first force 637 is a linear force applied along a first direction into a well bore. During maintenance, a second force 645 is applied on the reciprocating pump such that the shoulder portion 654 is detached from the second slot portion 692, thereby allowing the pump-shaft 632 to disengage from the driver-shaft 626. In one embodiment, the second force 645 is the linear force applied along a second direction away from the well bore.

FIG. 14 shows a schematic assembled view of a driver-shaft 726 coupled directly to a pump-shaft 732 of an artificial lift system in accordance with another exemplary embodiment.

The pump-shaft 732 includes a first peripheral end portion 780 and a second peripheral end portion 782. The pump-shaft 732 includes a plurality of tines 770 spaced apart from one another and extending along a circumferential direction from the first peripheral end portion 780 towards the second peripheral end portion 782. Further, the plurality of tines 770 protrudes beyond the first peripheral end portion 780 along a central axis 781 of the pump-shaft 732. Each tine 770 include a projection 772 detachably engaged to a notch 752 formed on the driver-shaft 726 such that the first peripheral end portion 780 is contacted to a peripheral end portion 748 of the driver-shaft 726. In the illustrated embodiment, a separate coupling member is not required because the pump-shaft 732 is detachably engaged directly to the driver-shaft 726. In certain other embodiments, the pump-shaft 732 may include the notch 752 and the driver-shaft 726 may include a plurality of tines 770, each tine including a projection 772. In such embodiments, the projection 772 is coupled to the notch 752 thereby detachably engaging the driver-shaft 726 to the pump-shaft 732.

In accordance with one or more embodiments discussed herein, a reciprocating pump is detachably engaged to a reciprocating driver within a production tubing of a well bore, thereby allowing the reciprocating pump to be easily and efficiently replaced independently of the reciprocating driver. As a result, service costs, time required for replacement/ repair of the reciprocating pump/reciprocating driver, and the amount of production downtime are reduced.

While only certain features of embodiments have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended embodiments are intended to cover all such modifications and changes as falling within the spirit of the invention. 

1. An artificial lift system comprising: a reciprocating driver comprising a driver-shaft; and a reciprocating pump comprising a pump-shaft detachably engaged to the driver-shaft.
 2. The artificial lift system of claim 1, further comprising a coupling member, wherein the pump-shaft is detachably engaged to the driver-shaft via the coupling member.
 3. The artificial lift system of claim 2, wherein one among the driver-shaft and the pump-shaft comprises a notch and wherein the coupling member comprises a first end coupled to other among the driver-shaft and the pump-shaft.
 4. The artificial lift system of claim 3, wherein the coupling member further comprises a second end and a plurality of tines extending from the second end up to a predefined distance towards the first end, wherein the plurality of tines is detachably engaged to the notch.
 5. The artificial lift system of claim 2, wherein the coupling member comprises a connecting member comprising a slot and a harpoon anchor detachably engaged to the slot, wherein the harpoon anchor is coupled to one among the driver-shaft and the pump-shaft and the connecting member is coupled to other among the pump-shaft and the driver-shaft.
 6. The artificial lift system of claim 2, wherein the coupling member comprises a connecting member comprising a slot and a shear pin detachably engaged to the slot, wherein the shear pin is coupled to one among the driver-shaft and the pump-shaft and the connecting member is coupled to other among the pump-shaft and the driver-shaft.
 7. The artificial lift system of claim 2, wherein the coupling member comprises a fishing-neck-like member and an overshot member detachably engaged to the fishing-neck-like member, wherein the fishing-neck-like member is coupled to one among the driver-shaft and the pump-shaft and the overshot member is coupled to other among the pump-shaft and the driver-shaft.
 8. The artificial lift system of claim 2, wherein the coupling member comprises a first connecting member comprising a slot and a spring collet comprising a shoulder portion detachably engaged to the slot, wherein the spring collet is coupled to one among the driver-shaft and the pump-shaft and the first connecting member is coupled to other among the pump-shaft and the driver-shaft.
 9. The artificial lift system of claim 8, wherein the shoulder portion is disposed substantially perpendicular to a central axis of the pump-shaft.
 10. The artificial lift system of claim 8, wherein the shoulder portion is disposed at a pre-determined tilt angle relative to a central axis of the pump-shaft.
 11. The artificial lift system of claim 8, wherein the coupling member further comprises a second connecting member, wherein the spring collet is coupled to the one among the pump-shaft and the driver-shaft via the second connecting member, wherein the second connecting member comprises a first end coupled to the spring collet and a second end comprising a slot.
 12. A method comprising: installing a reciprocating driver comprising a driver-shaft in a well bore; installing a reciprocating pump comprising a pump-shaft in the well bore; and applying a first force to the reciprocating pump, to detachably engage the pump-shaft to the driver-shaft.
 13. The method of claim 12, further comprising applying a second force to the reciprocating pump, to disengage the pump-shaft from the driver-shaft.
 14. The method of claim 13, wherein the pump-shaft is detachably engaged to the driver-shaft via a coupling member.
 15. The method of claim 13, wherein the second force comprises at least one of a linear force and a rotation force applied using at least one of a hydraulic pressure device, a pneumatic pressure device, a wire line device, a coiled tubing, and a plurality of sucker rods.
 16. The method of claim 12, wherein the first force comprises at least one of a linear force and a rotation force applied using at least one of a hydraulic pressure device, a pneumatic pressure device, a wire line device, a coiled tubing, and a plurality of sucker rods.
 17. A method comprising: powering a reciprocating driver disposed in a well bore, wherein the reciprocating driver comprises a driver-shaft; driving a reciprocating pump disposed in the well bore via the reciprocating driver, wherein the reciprocating pump comprises a pump-shaft detachably engaged to the driver-shaft; and pumping a production fluid from the well bore to a surface unit via a tubing, by driving the reciprocating pump.
 18. The method of claim 17, wherein the pump-shaft is detachably engaged to the driver-shaft via a coupling member.
 19. The method of claim 18, wherein driving the reciprocating pump comprises transmitting a compressive force directly from the driver-shaft to the pump-shaft.
 20. The method of claim 18, wherein driving the reciprocating pump comprises transmitting a tensile force from the pump-shaft to the driver-shaft via the coupling member. 